The Labour party was originally a party of the trade unions, founded when many working men, and all women, had no vote and when trade unions faced fierce legal challenges that threatened their very existence. More than a century on, Britain is a very different place. But in post-industrial Britain, only a minority of workers are now in unions – 6.5 million at the last count, half the total of the 1970s peak, and now just 26% of the workforce. Membership is concentrated in the public sector, while in the private sector, where the workforce is four times larger, membership is a mere 14%. The Labour party has always had to evolve to reflect and embrace a changed society, while not losing sight of its roots and values. If it is to thrive and achieve a majority among the voters it must do so again. It did this at the beginning and end of the 20th century and now faces the same need at the start of the 21st.

No one can say whether Ed Miliband would have tackled this issue if his hand had not been forced by the furore surrounding Labour's candidate selection in Falkirk last year. Given that Mr Miliband won by a whisker under the existing party electoral college voting system, which largely dates from 1981 and gives the unions a third of the votes in leadership elections, he might have been tempted to let things lie. But a combination of Falkirk, some bumptious union interventions, rightwing press hostility and Labour's struggle to build a winning share in the polls – plus, it should be said, the Labour leader's own strong sense of fairness – have compelled him to reopen the question of party democracy. The results have been the Collins review, not yet published, and the proposals that Mr Miliband discusses in a Guardian interview, which will now go before a special party conference in a month's time.

Mr Miliband's approach is evolutionary not revolutionary. He is not aiming to break or abandon the trade union link – for which some, mainly outside Labour, will criticise him. But he certainly wants to change the link, and he certainly wants to put those changes in the wider frame of an attempt to open up party membership far beyond the public sector union core. If Mr Miliband gets his way, Labour will have three main categories of formal supporters: individual members, individual affiliated supporters (mainly union members) and registered supporters (effectively a cheaper system of individual membership). All will have a vote in leadership elections, while the electoral college will be scrapped. These changes bring Labour very close to being an individual membership party (as most of its rival parties already are, at least for leadership election purposes) while preserving in a much changed form the historic relationship with organised labour that Mr Miliband rightly cherishes.

In some respects all this is a compromise with the union leaders who partly created the problem. That will inevitably arouse suspicions. The block vote at party conference will stay and only be fully addressed in five years. There is nothing yet about changes to the national executive elections. The new membership schemes will be given time to work – and may prove to have loopholes at constituency level as well as in the unions. Meanwhile unions will still have political funds from which they can make very large donations to the party.

But the reforms are nevertheless a genuine and vernacular attempt to open up Labour to more members and supporters – and Britain needs vibrant political parties. Vitally, the changes break the power of union leaders to direct and control the way their members vote, since all votes will be issued and returned directly to the party, not via a union intermediary. It is potentially a huge blow to the politics of the secret fix, which has bedevilled Labour for years. Yet if it helps to fix what is wrong in the Labour system and to help fix politics more generally, it could prove to be worthy work.